When my psychiatrist wisely titrated me on Zoloft (Setraline), he made me do little jumps at 12.5mg every week, and those smaller jumps were noticeable with my body, but they were manageable. I could still operate at work, even though I could feel the Setraline working in my body. However I can't imagine jumping from 100mg to 150 in one day. I hope your jump feels comfortable.
In terms of how long will Setraline work, it will take about three months to get stable at a decent dose (100mg to 150mg). If you're at 100mg, you may want to stay there for another week, since your brain is still adjusting. At four weeks, you're only about 40% of your way to stabilization, since an antidepressant will basically take 12 weeks to be stable in your system at a dosage above 100mg. But you will feel improvement with each passing week, not each passing day.
If you're off work until February, take advantage of the free time, and get your mind off your mental health problems. The most important thing is to have the medication in your system, as you allow it to work. Watch movies on NetFlix. There are so many movies I've missed out from last year, that I would love to have the extra time to watch. Read good books, although try to avoid the self help books, because your focus will always be on your health problem. Just read things that just make you feel good.
But most important, keep in contact with your doctor. I think you'll need too regardless, since he provides your progress to your employer with your Family Medical Leave.